Stabilization of print-out emulsion images



United States Patent 6 STABILIZATION OF PRINT-OUT EMULSION IMAGES Francis H. Gerhardt, John Proc, and Joseph Sottysiak, Binghamton, N.Y., assignors to General Aniline & Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Application December 31, 1956 Serial No. 631,497

8 Claims. (Cl. 96-61) The present invention relates to photographic images and, in particular, to the stabilizing of print-out emulsion images to the further action of actinic light.

Print-out emulsion coatings have been known to the photographic art for many years. Such coatings usually consist of a silver chloride emulsion and are characterized by a relatively low speed although recently silver chlorobromide print-out emulsions have appeared wherein the speed is considerably higher than the older chloride types.

Since print-out emulsion images are not fixed, exposure to actinic light results in further development so that permanent images are not possible. Due to the aforesaid limitation, the use of print-out emulsions has been largely confined to the proofing media where permanency was not required as in the case of the photo finishing trade. However, with the increasing application of print-out emulsion coatings, both on paper and film base, in industrial installations, the need has arisen for stable images so that permanent records and files may be kept.

It has been proposed to stabilize print-out images by a toning process involving the use of solutions of gold, platinum, or palladium salts. However, this technique is unsatisfactory when applied to the newer high speed print-out emulsions.

It is, therefore, an object of the present invention to provide permanent print-out images which are stable to the further action of actinic light.

It is another object to provide a method and means for producing permanent print-out images which are stable to the further action of actinic light.

Other objects will become apparent as the description proceeds.

It has been found that print-out images can be permanently stabilized by treating the said images with an aqueous solution of a fixing composition containing as its essential components, an alkali metal or ammonium thiosulfate, thiourea, and an alkali metal or ammonium halide.

Preferably, the ammonium thiosulfate is used with the thiourea. While it is possible to use either an alkali metal or ammonium halide such as the bromide or chloride, we find that better results ensue if both an alkali metal and an ammonium halide are present.

The composition in addition to the aforementioned essential components may also contain other adjuncts which facilitate the fixing operation such as an alkali metal sulfate, i.e., sodium sulfate, an alkali metal sulfite, i.e., sodium sulfite, and a boron compound such as boric acid.

Finally, the composition may contain a higher molecular weight water soluble colloid such as the sodium salt of a condensate of a fatty acid with a protein hydrolysate, such as lysalbinic acid or a sodium salt of carboxy methyl cellulose as a thickener so that the fixing composition may be rolled or pressed onto the print-out emulsion print or film and squeegeed to obtain intimate contact in all areas. Such a technique would be useful in those instances where bulky tanks of fixing solution would be objectionable or undesirable.

The exposed print-out images are immersed in the aforesaid fixing baths for periods ranging from 30 seconds to 5 minutes. A short washing period is recommended for more permanent prints.

The details of the invention are presented in the following examples but it is to be understood that the invention is not limited thereto.

EXAMPLEI A composition for stabilizing print-out imageswas prepared as follows:

Thiourea gms 40 Ammonium thiosulfate gms 40 Sodium sulfate gms 20 Water cc 1500 The print is immersed in the above solution for a period of 3 to 5 minutes, is then washed for 30 minutes in slowly running water, and then dried. During the above opera tion, the processing solution should not exceed 68 F. In the case of film base coatings, a prefixing or hardening treatment is necessary in order to properly stabilize the image and prevent mechanical removal of'the emulsion from the base.

A print is immersed in solution A for a period of 20 to 30 minutes. If the print becomes tacky, it is placed in solution B for 2 minutes and then immersed in solution C for 5 to 10 minutes. The print is then washed slowly in running water for 20 minutes and dried.

Film coatings may also be treated in the same manner.

As in the case of Example I, the temperature of the processing solutions should not exceed 68 F.

EXAMPLEIII Thiourea gms 40 Ammonium thiosulfate gms 40 Ammonium chloride gms 15 Sodium sulfite gms 15 Potassium bromide or chloride gms 40 10% aqueous solution of the sodium salt of a condensate of a fatty acid with a protein hydrolysate mls 8 10% aqueous solution of monodiethylaminoethyldodecenyl succinate mls 2 Water a liter 1 The print is immersed in the above composition for a period ranging from 30 to 60 seconds. It is then removed from the stabilizing bath and air dried. In the eventthat ajmore permanent print is desired, a short wash of ap- Thiourea gms 40 Ammonium thiosulfate gms 4Q Ammonium chloride gms '15 Sodium sulfite. ...L gms 15 Potassium bromide'or chloride gms 40 10% aqueous solution ofthe sodium salt of a condensate of a fatty acid with a protein hydrolysate mls 8 10% aqueous solution of monodiethylaminoethyldodccenyl succinate mls 2 Water mls 500 The' above viscous solution is imbibed or absorbed into a porous sheet of paper and then dried. This fixer sheet is then employed to effect fixation or stabilization of print-out images in the following manner.

The fixer sheet is thoroughly wetted with water, pressed against the emulsion side of the print and squeegeed to obtain intimate contact in all areas. ously accomplished by means of a small print roller. Again it should be emphasized that good contact between fixer sheet and print is necessary in order to eifect proper stabilization of the print; After a period of 1 to 5 minutes, the fixer paper is removed and the print allowed to We claim:

' 1. A method for stabilizing print-out images in silver halide print-out emulsions. which comprises treating said images uniformly after exposure to light with a composition'comprising anaqueous solution of a metal thiosulfate of the formula M 8 0 wherein M is selected from the class consisting of ammonium and the alkali metals, thiourea, and a water soluble halide of the class consisting of ammonumhalides and the alkali metal halides.

l "2. The process as defined in claim 1 wherein the said composition also contains an alkali metal sulfite.

This is advantage- 3. A method according to claim 1 wherein M is am- 4 halide print-out emulsions which comprises treating said images uniformly after exposure to light with a composition comprising an aqueous solution of a metal thiosulfate of the formula M 8 0 wherein M is selected from the class consisting of ammonium and the alkali metals, thiourea, a halide of ammonium, and the sulfateof an alkali metal. 7

5. A method according to claim 4 wherein M is ammonium, the ammonium halide is ammonium chloride and the alkalimetal sulfate is sodium sulfate.

'6. A'method according to claim 4 wherein M is sodium, the ammonium halide is ammonium chloride, and the alkali. metal sulfate is sodium sulfate.

7. A method for stabilizing print-out images insilver halide print-out emulsions after exposure to light which comprises applying a wetted porous sheet to said images in a manner to obtain intimate uniform areal contact betweenthe emulsion side of the print and the said porous sheet which porous sheetha's absorbed within its structure a fixing composition comprising an aqueous solution of a metal thiosulfate of the formula M 3 0 wherein M is selected from the class consisting of ammonium and the alkali metals, thiourea, an ammonium halide, an alkali metal halide, the suliite of an alkali metal and a viscosity increasing agent consisting of a high molecular weight water soluble colloid.

8. A method according to claim 7 wherein M is ammonium, the ammonium halide is ammonium chloride,

the alkali metal halide is potassium bromide, the alkali metal sulfite is sodium sulfite, and the high molecular weight water soluble colloid is the sodium salt of a condensate of a fatty acid with a protein hydrolysate.

2,083,675 Ville June 15, 1937 OTHER REFERENCES Clerc: Photography Theory and Practice, second edition (1937), pp. 354357. (Copy in Div. 60.)

Henuey et al.: Handbook of Photography, McGraw- Hill, New York N.Y., 1939, pages 146, 386, 387, 451 and 452; (Copy in Scientific Library.)

Land Feb. 27, 1951 

1. A METHOD FOR STABILIZING PRINT-OUT IMAGES IN SILVER HALIDE PRINT-OUT EMULSIONS WHICH COMPRISES TREATING SAID IMAGES UNIFORMLY AFTER EXPOSURE TO LIGHT WITH A COMPOSITION COMPRISING AN AQUEOUS SOLUTION OF A METAL THIOSULFATE OF THE FORMULA M2S2O3, WHEREIN M IS SELECTED FROM THE CLASS CONSISTING OF AMMONIUM AND THE ALKALI METALS, THIOUREA, AND A WATER SOLUBLE HALIDE OF THE CLASS CONSISTING OF AMMONUM HALIDES AND THE ALKAI METAL HALIDES. 